Building a diypnp, Standalone harness wiring Options

[HardHead93]

I have been having nothing but trouble with my AEM FIC on my 5sfte set up. I have a 97 Celica GT Convertible with a newly rebuilt engine and a 16G CT-26 turbo set up. The ECU is not working well with the signals the piggyback is feeding the stock ECU. Based on a couple of posts I have seen on 6gc.net, I broke down and bought a diypnp 76 pin standalone. The diypnp has all the features I am looking for and the price doesn't break the bank. I just finished soldering the main board and am about to start doing the harness jumpers. Can anyone provide and example for wiring the diypnp?

[lagos]

Here is the basic idea:

1. Don't connect any of the AC related functions that exist on the OEM ECU to Megasquirt and verify that the AC works just fine without them (with the exception of the idle up functionality).

2. Find the wire that sends the ground switching control signal to the AC relay located in the engine bay on the passengers side of the car. You want to cut this wire and have Megasquirt intercept this signal.

3. Once you have the wire cut, connect the signal side of the wire directly to the Flex input. No need to run this through any MS relays.

4. Connect the PA0 pin to Relay1 IN on Megasquirt, and connect Relay1 OUT directly to the AC relay in the fuse box.


In this configuration Megasquirt will see that the factory ac amp wants to turn on the AC and will delay this signal by a few seconds so that it can idle the engine up first to create a smooth transition. I will take a look at my wiring book and let you know the color of the wire that goes to the AC relay.

This post has been edited by lagos: Aug 31, 2016 - 11:03 AM

[HardHead93]

Here is the basic idea:

1. Don't connect any of the AC related functions that exist on the OEM ECU to Megasquirt and verify that the AC works just fine without them (with the exception of the idle up functionality).

2. Find the wire that sends the ground switching control signal to the AC relay located in the engine bay on the passengers side of the car. You want to cut this wire and have Megasquirt intercept this signal.

3. Once you have the wire cut, connect the signal side of the wire directly to the Flex input. No need to run this through any MS relays.

4. Connect the PA0 pin to Relay1 IN on Megasquirt, and connect Relay1 OUT directly to the AC relay in the fuse box.


In this configuration Megasquirt will see that the factory ac amp wants to turn on the AC and will delay this signal by a few seconds so that it can idle the engine up first to create a smooth transition. I will take a look at my wiring book and let you know the color of the wire that goes to the AC relay.

Is this the wire that needs to be cut? I have it circled in red. It looks like it goes to the MGC pin on the AC amplifier.

[HardHead93]

I did some researching and figured out how to get the idle up to working by using the AC1 pinout on the ECU! I did the following.
1. Connected the PAO to the RELAY1 IN on the Megasquirt and the RELAY1 OUT to the engine ground.
2. Connected the FLEX on the Megasquirt to the AC1 pinout.
3. In Tunerstudio in the Air Conditioning Idle Up screen I set the output to PAO, the input to FLEX, and the Idle-Up Input polarity to Low.
That was it, every time I turn on the AC within a few seconds the DIYPNP recognizes the AC compressor is on and idles up the engine. I was going to tap into the AC Relay like Lagos said but that would defeat the purpose of me chosing the Megasquirt. My goal is to cut into the factory wiring as little as possible to avoid causing some damage I could not repair. So far the only wire I had to cut for the Megaquirt was the intake air temp sensor harness to add a GM sensor. I figured if the stock ECU can idle up with the AC1 input then so can the Megasquirt. Lagos, thanks for all the help in figuring out this ECU. I would not have been able to track this problem down without your help.

Another problem I am recognizing is that the DIYPNP is very limited on additional features remaining if you go with the sequential injection mod. If I want to use a boost controller, I am out of ports for that function. The PAO, PT6, and PT7 are the only ports that can use a boost controller. When you go sequential injection, PT6 and PT7 taken to control the injectors and if you attempt to use them Tunerstudio will give you a config error. With me using the PAO for the AC idle up, I have nothing left to run a boost controller unless I switch back to batch fire injection and reclaim the PT6 and PT7 ports for use. Are there any other options?

This post has been edited by HardHead93: Sep 2, 2016 - 6:25 PM